Implantable controls for cardiac pacemakers



A11g- 1965 w. M. CHARDACK 3,198,195

IMPLANTABLE CONTROLS FOR CARDIAC PACEMAKERS Filed Oct. 18. 1962 INVENTOR.

OFF

PULSE PRODUCING Cuzcun' ATTORNEYS.

United States Patent 3,198,195 IMPLANTABLE CQNTROLS FQR CARDIACPACEMAKERS William M. Char-deck, 144 Ivyhurst Road, liuifalo, N.Y. Filed0st. 18, 1962, Ser. No. 231,349 Claims. (Cl. 128-419) This inventionrelates generally to electrical pulse generating devices, known aspacemakersflfor stimulation of the heart, and more specifically to newand useful rate and amplitude controls for such devices.

Various pacemaker devices have been developed for providing suitablestimulating current pulses to the heart. Some of these devices areexternal, some are suitable for complete implantation within the body,and some are partly external and operate by induction through the intactskin to a subcutaneous coil. The completely implantable units have theadvantage, over those which are entirely or partially external, that thepatient need not carry about or be concerned with any externalattachments or appliances. However, completely implantable pacemakersheretofore have had the relative disadvantage that the rate andamplitude of the current pulse could not be adjusted. In addition, theyhad the further disadvantage that they commenced operation as soon astheir manufacture was completed, and could not be turned off prior touse. For this reason, prolonged storage in sterile condition was notpossible with out encroaching upon some of the battery life.

,it is desirable to be able to restore the basic pulse rate. Inaddition, it may in some patients be desirable to change the pulse rate,for example to deal with unusual situations such as intercurrent orcoexisting disease requiring a temporary increase in cardiac output.Also,

.in the case of children, who normally require a higher pulse rate thanadults, it is desirable to decrease the pulse rate as the child growsup.

Amplitude control is desirable, to permit stimulation at levels justabove the threshold requirements of the particular patient.

Any greater amplitude merely reduces the total battery life, and mayproduce undesired physiological results.

Accordingly, a primary object of my invention is to provide rate andamplitude controls for implantable pacemaker devices, which controls areimplantable with the pacemaker and can be actuated by making a simplepercutaneous puncture.

- Another object of my invention is to provide completely implantablerate and amplitude controls as aforesaid which can be located andidentified, after implantation, by palpation through the intact skin.

Still another object of my invention is to provide an on-olf controlimplantable with the pacemaker and which can be actuated by making asimple percutaneous puncture.

-A pacemaker control constructed in accordance with my invention ischaracterized in one aspect thereof by the provision, in combinationwith an implantable cardiac pacemaker, of an adjustable componentoperable to vary an output characteristic of the pacemaker, and means.for adjusting the component including means for receiving a skinpuncturing instrument, the adjusting means being encased within apuncturable shield of material compatible with the human body as anenvironment for subcutaneous implantation of said control with saidpaceis characterized by the provision, in combination with an iceimplantable cardiac pacemaker having a housing of an adjustablecomponent operable to vary an output function of the pacemaker, andmeans for adjusting the component, the adjusting means including meansfor receiving a skin puncturing instrument, the control beingimplantable with the pacemaker and the instrument receiving meansprojecting beyond the main portion of the pacemaker housing for locationby palpation.

The foregoing and other objects, advantages and characterizing featuresof my invention will become clearly apparent from the ensuing detaileddescription of a presently preferred embodiment of my invention, and onemodification thereof, taken in conjunction with the accompanying drawingillustrating the same wherein like reference numerals denote like partsthroughout and wherein:

FIG. 1 is a plan view of an implantable pacemaker incorporating the rateand amplitude controls of my invention, the electrode leads being brokenaway for convenience in illustration;

FIG. 2 is a view on an enlarged scale, partly in longitudinal sectionand partly in elevation, through one of the controls of FIG. 1;

FIG. 3 is a side elevational view of a standard bayonet type Keith skinneedle, with which the rate and amplitude controls of my invention canbe percutaneously actuated;

FIG. 4 is a side elevational view of an adaptor form ing part of thecontrol of FIG. 2;

FIG. 5 is an end elevation thereof;

FIG. 6 is a view similar to that of FIG 2 but with certain parts omittedfor ease of illustration and show ing a modified construction; and

FIG. 7 is a diagrammatic view of a control portion of the pacemakerpulse producing circuit.

There is shown in FIG. 1 an implantable pacemaker having a housinggenerally denoted 1 and comprising, with the exception of the rate andamplitude controls to be described, a pacemaker of a type which is knownper se. Such pacemakers have for some time been manufactured byMedtronics, Inc., Minneapolis, Minnesota under the nameChardack-Greatbatch Pacemaker, and are of the type described in detailin Patent 3,057,356 issued October 9, 1962 in the name of WilsonGreatbatch, to which reference is hereby made for such details.Accordingly, a detailed description thereof is not essential to anunderstanding of this: invention, for purposes of which it is onlynecessary to say that pacemaker housing 1 comprises a pulse producingcircuit in the form of a mercury cell driven, miniaturized blockingoscillator and amplifier, cast in a potting compound (such as the epoxyresin shown at '19 in FIG. 2) and enclosed in a thin envelope ofsuitable material, such as the inner silicone rubber layer 22 of FIG. 2.The rate and amplitude of the output pulse are controlled, in accordancewith my invention, by adjustable com ponents, such as the variableotentiometers generally denoted 2. The pulse is transmitted via leads 3to a pair of electrodes, not shown, preferably of the type set forth inmy pending application Serial No. 171,189 filed February 5, 1962.

While the circuit connections thereof will differ, so as .to controlrate on the one hand and amplitude on the other, the operation ofpotentiometers 2 otherwise is identical, and therefore only one thereofwill be described in detail. H

Referring now to FIG. 2, it is seen that each potentiometer 2 contains aworm wheel 4 or the like to which a movable potentiometer element 23'('FIG. 7) is connected for being driven across resistance 23 uponrotation of wheel 4 by worlm 5. These parts are enclosed within achamber defining enclosure 6, from which extend leads 24 into thepacemaker circuit being controlled.

The potentiometer 2 shown in FIG. 2 is conventional, per se, andalternative types of potentiometers obviously can be used. Worm 5extends through enclosure 6, terminating externally thereof in anenlarged head 7 slotted to receive a screwdriver bit. A locking key 8engages a groove in the worm shaft, to hold worm 4 in axial position,and a seal 9, such as an O-ring of neoprone rubber, is carried byenclosure 6 in sealing engagement with the worm shaft.

It will be apparent that the resistance of potentiometer 2 can be variedby rotating head 7 and worm 4. The

problem is to do this percutaneously, when the potentioit is larger indiameter than worm head 7, and the opposite ends of bit 11 are axiallyelongated, as indicate-d at 5, and extend downwardly along worm head 7on opposite sides thereof, below the bit receiving groove. This servesto more securely position adaptor til on the head 7.

The needle shaft is guided into engagement with adaptor slot 12 by anouter sleeve 16 having an enlarged bore receiving and containing theadaptor for rotation therein. Adjacent thereto, sleeve 16 has afrusto-conical bore 18 tapering inwardly toward the adaptor recess 12.Thus, when needle shaft 13 is inserted in sleeve bore 18, it is guidedthereby into the adaptor recess 12, for rotating the latter to turn worm5 and wheel 4 upon rotating needle 14 about its lengthwise axis. Sleeve16 has a flat-sided extension 19 extending downwardly along one side ofpotentiometer enclosure 6 and abutting the same to prevent rotation ofthe sleeve thereon. Sleeve extension 19 is secured to enclosure 6 by anadhesive epoxy resin.

The pacemaker and its controls must be body fluid proof, and thispresents a problem which is solved as follows. The sleeve bores 17 and18, and adaptor recess 12, are filled with a sealing material 20penetrable by needle shaft 13. Material 20 should be well tolerated bysurrounding body tissue, and non-adherent to needle 14 so as not .to becarried outwardly thereby when the needle is withdrawn. A suitablematerial is a silicone high vacuum grease. Several layers 21 and 21" ofa shielding material are then applied over the assembled potentiometer2, adaptor 10 and sleeve 16. Material 21 and 21" must be non-toxic tosurrounding body tissue and compatible with the human body as anenvironment. Dow Corning silicone rubber compound-s are uitable, andsome of these have the added advantage of bonding to metal. The entireassembly then is sterilized by heat, prior to incorporation into thepacemaker.

In use, the rate and amplitude controls are completely implanted withthe pacemaker. This poses the problem of locating and identifying thecontrols when adjustment is required. To accomplish this, sleeve 16 andthe surrounding shielding layers are arranged to provide each controlwith a nubbin 2-2 projecting from the main portion of the pacemakerhousing 1, as shown in FIG. 1. Nubbins 22 are of sufiicient diameter andlength as to be readily palpatable. Thus, the physician desiring toadjust either rate or amplitude can palpate the area and determine byfeel alone the location of the two adjustment controls. Further, toenable identification of one nubbin 22 from the other by palpationalone, one of the .control nubbins 22 is positioned closer to thejuncture of leads 3 with body 1 than the other control nubbin 22. Forexample, assume that it is the amplitude control nubbin 22 which isclosest to the juncture of electrode leads 3 and body 1, and whichtherefore is the left hand nubbin in FIG. 1. The physician, being alsoable to palpate the leads 3 at their juncture with body 1, can determineby feel alone, through the intact skin, which control nubbin is the onehe wants. He then can manipulate that control by inserting needle 14through the skin, and through theshielding portion 23 overlying theouter end of sleeve bore 18. The needle will be guided by the sleeve 16into the adaptor recess 12. Once it is received therein, as determinedby the resistance to further insertion, the physician rotates the needlein the direction required to achieve the desired adjustment.

While the grease 2.9 is non-toxic to surrounding tissue, its escapethrough shielding material 21 and 21" nonetheless is not desired.Accordingly, the silicone shielding material, at least in the area ofportion 21', is sufficiently resiliently yieldable to expand and therebyaccommodate displacement of the silicone grease 2i) upon insertion ofneedle .13. This prevents displacement of the grease along the needleshaft through the needle juncture in the shielding portion 21.

FIG. 6 shows a modified arrangement in which potentiometer 2 is providedwith a worm head 7' having a recess 12 for directly receiving the skinneedle, in which case the separate adaptor It can be dispensed with. Theoperation remains the same as described above.

It will be appreciated that, in the case of rate control, potentiometer23-23 can be substituted for resistor 22 in the timing circuit shown inthe aforesaid Patent 3,057,- 356. For amplitude control, potentiometer23-23 can be connected in series in the output circuit of said patent,as indicated at 24 (FIG. 7). Each potentiometer is provided with an offposition, whereby the pacemaker can be turned on and off by percutaneouspuncture.

Accordingly, it is seen that my invention fully accomplishes itsintended objects, and provides completely implantable pacemaker rate andamplitude controls which can be activated by simple percutaneouspuncture. While I have disclosed in detail only one embodiment of myinvention, and a modification in a part thereof, that has been done byway of illustration only, it being my intention to be limited only bythe scope of the appended claims.

Having fully disclosed and completely described my invention, and itsmode of operation, what I claim as new is:

1. In combination with an implantable cardiac pacemaker compatible withthe human body as an environment and having a housing and an electrodelead extending therefrom, percutaneously actuated controls implantablewith said pacemaker beneath the skin of the human body for varyingdifferent output characteristics of said pacemaker comprising a firstadjustable component in said housing operable to vary one outputcharacteristic of said pacemaker, a second adjustable component in saidhousing operable to vary another output characteristic of saidpacemaker, means for adjusting said first component including firstmeans carried by said housing for receiving a skin puncturinginstrument, means for adjusting said second component including secondmeans carried by said housing for receiving a skin puncturinginstrument, said first and second means projecting from the main portionof said pacemaker housing in spaced relation to each other and to thejuncture of said lead and said housing, and one of said first and secondmeans being positioned closer to said juncture than the other thereof,whereby said first and second adjusting means can be located andidentified by palpation, said projecting adjusting means being encasedwithin a shield of material puncturable by a skin puncturing instrumentand compatible with the human body as an environment.

2. In combination with an implantable cardiac paceensures makercompatible with the human body as an environment and having a housing, apercutaneously actuated control implantable with said pacemaker beneaththe skin of the human body for varying an output characteristic of saidpacemaker comprising an adjustable com ponent in said housing operableto vary such output characteristic, and means for adjusting saidcomponent including a part carried by said housing and engageable by askin puncturing instrument and a sleeve carried by said housing andassociated with said part for guiding a skin puncturing instrument intoengagement therewith, said sleeve projecting from the main portion ofsaid housing for location by palpation, said projecting sleeve beingencased within a shield of material puncturable by a skin puncturinginstrument and compatible With the human body as an environment.

3. In combination with an implantable cardiac pacemaker compatible withthe human body as an environment, a percutaneously actuated controlimplantable With said pacemaker beneath the skin of the human body forvarying an output characteristic of said pacemaker comprising anadjustable component operable to vary such output characteristic, andmeans for adjusting said component including a part engageable by a skinpuncturing instrument and a sleeve associated with said part for guidingsuch an instrument into engagement therewith, the interior of saidsleeve being filled with a sealing grease, and a shield of puncturablematerial enclosing said sleeve, said material being compatible with thehuman body as an environment.

4. A control as set forth in claim 3, wherein said material issufliciently resiliently yieldable to accommodate displacement of saidgrease upon penetration thereof by such an instrument.

5. In combination with an implantable cardiac pacemaker compatible Withthe human body as an environment, a percutaneously actuated controlimplantable with with said pacemaker beneath the skin of the human bodyfor varying an output characteristic of said pacemaker comprising anadjustable component operable to vary such output characteristic, amember connected to said component and movable to adjust the same, andmeans connected to said member and engageable with a skin puncturinginstrument for movement thereby to so move said member, said component,member and means being carried by said pacemaker and being encasedwithin a puncturable shield of material compatible with the human bodyas an environment for subcutaneous implantation of said control withsaid pacemaker, wherein said component is enclosed within a chamberdefining enclosure, said member being journaled in said enclosure andhaving a part exteriorly of said enclosure, said part having a firsttool receiving formation, said means comprising an adaptor engaging saidfirst tool receiving formation and having a second formation engageablewith a skin puncturing instrument.

References Cited by the Examiner UNITED STATES PATENTS 3,050,695 8/62 DuVall 128421 3,057,344 10/62 Abella 1282 3,057,356 10/62 Greatbatch128422 3,093,136 6/63 Lohr 128-423 3,109,430 11/63 Tischler 128-422RICHARD A. GAUDET, Primary Examiner.

LOUIS R. PRINCE Examiner.

1. IN COMBINATION WITH AN IMPLANTABLE CARDIAC PACEMAKER COMPATIBLE WITHTHE HUMAN BODY AS AN ENVIRONMENT AND HAVING A HOUSING AND AN ELECTRODELEAD EXTENDING THEREFROM, PERCUTANEOUSLY ACTUATED CONTROLS IMPLANTABLEWITH SAID PACEMAKER BENEATH THE SKIN OF THE HUMAN BODY FOR VARYINGDIFFERENT OUTPUT CHARACTERISTICS OF SAID PACEMAKER COMPRISING A FIRSTADJUSTABLE COMPONENT IN SAID HOUSING OPERABLE TO VARY ONE OUTPUTCHARACTERISTIC OF SAID PACEMAKER, A SECOND ADJUSTABLE COMPONENT IN SAIDHOUSING OPERABLE TO VARY ANOTHER OUTPUT CHARACTERISTIC OF SAIDPACEMAKER, MEANS FOR ADJUSTING SAID FIRST COMPONENT INCLUDING FIRSTMEANS CARRIED BY SAID HOUSING FOR RECEIVING A SKIN PUNCTURINGINSTRUMENT, MEANS FOR ADJUSTING SAID SECOND COMPONENT INCLUDING SECONDMEANS